Plaster board



March 9 ,1926. 1,576,141l

v J; N. SCHUMACHER PLASTER BOARD 1 Eiled Nov; 1s, 1924 ATTORNEYS.,

Patented M8439, l1926. l

UNITED STAT-as` PATENT OFFICE..

JHN N. SCHUMACHER, OF LOS ANGELES, CALIFORNIA.

rLAs'rER BOARD.

i Apancaamimed November 1s, 1924. serial No. 749,676.

. in the manufacture of such articles to provide a method and material whereby the.

adhesion of the covering sheets and cementitious body is amaximum, and the board in its green state-has characteristics permitting handling without damage. The time interval required for setting of ,the plaster` body is an appreciable element in the production. Any method or means which Will decrease the time element is desirable.

rIhe primary objects of this invention are to pro-vide an article of the character de' scribed and a method for producing the same which will decrease the time interval, maintain the quality of the article, and provide economy in manufacture.

'.lhese objects together W1th other objects and corresponding accomplishments are obtained by means of the embodiment of my invention illustrated inthe accompanying` f drawing. 1n Whlch:

Fig. l is a fragment of the lengthIof plaster board constructed in accordance With my invention; and Fig. 2 is atransverse section through an edge thereof on an enlarged scale. l,

Referringmore particularly to thedraw- D, a cementitious body 3 is shown interposed body '3 is'preferably made `of quick setting plaster. The -covering sheets 4 and jare preferably ofpapefso treated asv to be slow- 4 1 day of November 1924:. placed against the quick setting plaster, the 1 resultant adhesion of the paper to the plasly permeable 4to moisture. With the paper between-covering sheets 4 and .5. Thel ter body would not reach the qualitydesired as the plaster would set before the moistureA uould permeate the covering sheets sui.' Aclently to form a goed bond. My invention resides particularly in the treatment whereby a satisfactory. l. adhesion is obtained. Quick settingv plaster decreases thevtime element required for productionofthe board.

In order to overcome these'objectio'ns, I coat the inner face of each coverin sheet with a layer of retarded plaster. Thls plasr ter will form a good bond with the body 3 and a 'satisfactory bond With 'the covering sheet. rlhe layers'of retarded plaster are indicated by 6 and'7, and are in effect laminations. These laminations maybe pro- ,duced by passing. the covering' sheets in contact With plastic retarded plaster lso that the latter Will cling thereto, and then interposing the plaster board 3 therebetween' in the manner Well known lin the art,

The plaster body ,3 Willset quickly pro- I ducinga board stiff enough to handle Without injury in a .very short interval of ti'me. The laminations of V'retarded plaster board will assure a satisfactory adhesion between the covering sheets and the body.

What4 I claim is:

1. `An article of the. character described comprising a quick lsetting ceinentitious body, acovering sheet of pliable material slovvly permeable to moisture, and a lamination 'of retarded cementitious material binding said sheet and said body.

2. An article of the character described comprising a body of quick setting plaster interposed between pliable sheets slowly permeable to moisture, and laminationsof retarded plaster disposed on the outer faces `of said body and binding said sheets and body.

In Witness that I claim the foregoingl` have hereunto subscribed myl name this 3rd 

